If Nintendo had stuck to its original plan, Super Mario Galaxy 2 would have been Super Mario Galaxy 1.5 - and would have come out a year and a half ago.
You've heard it all before: Galaxy was awesome, Galaxy 2 looks great, do very, VERY want, etc - my excitement for Super Mario Galaxy 2 is no secret.
What was secret, though - at least, until now - is that we could have gotten Galaxy 2 much earlier ... but it would have also been a much smaller game. Speaking with Nintendo boss Satoru Iwata, Mario's creator Shigeru Miyamoto said that he originally told his staff to think of the game as Super Mario Galaxy 1.5 so they wouldn't work themselves too hard, according to Andriasang.
The original plan had been to deliver something like Zelda: Majora's Mask: A smaller sequel, with a development time of approximately a year - Galaxy 1.5 was intended to be in stores at the end of 2008. Of course, once the team buckled down and got to work, they looked back at the original game and noticed "areas where they felt they hadn't fully utilized the qualities of the sphere-based design."
Before long, "over 90 percent of the courses were new, and it was difficult to see where the old stage layouts were" - what started as "1.5" had officially become "2." Since they had already nailed down the problems relating to cameras and Mario's movement with the first game, all of the development time was laser-focused on new stages, items, and the tuning thereof.
Unfortunately, it also meant that the game took an extra year-and-a-half to develop than had been originally planned, with the game now scheduled to come out on May 23rd. On the other hand, it may well have been worth it - Galaxy 2 garnered a 10 from the notoriously harsh Edge.
Personally, I'm satisfied with waiting an extra year and a half for a great game. I mean, I'm a fan of both Blizzard and Valve - it's not like I'm not used to it.